In certain prior art, optical and ultrasonic sensors can be used to estimate the level of material inside of a container. However, the performance of optical and ultrasonic sensors is degraded by dust, dirt and airborne contaminants that may lead to erroneous estimated levels of material in a container. For example, if the container for a row of a planter is fed with seed material, erroneous estimated levels may result in overflowing of the container or the absence of planted seeds in a row, segment or area of a field. Thus, there is a need for a sensor and method for measuring a bin level via and electromagnetic signal.